Aerobic decomposition is a well-known method for disposing of unwanted food waste. It is useful in that it diverts food waste from landfill, which is generally agreed to be expensive, environmentally unfriendly and unsustainable.
Food security is a growing issue all over the World, and many Governments have made reducing food waste from domestic and commercial premises a priority in a bid to combat the growing threat. In addition, disposal of food waste can be difficult and expensive and a reduction in food waste levels has a direct impact on disposal costs, and on the environment. Food waste has a very high embedded energy cost, because often it has been grown, stored, transported, processed, packaged, refrigerated and cooked before being thrown away. Any method of reducing food waste therefore has a positive and direct impact on the environment.
Commercial foodservice operations often generate high levels of food waste. It is extremely difficult to efficiently and accurately measure levels of food waste because of the relatively high volumes involved, and without accurate information it is very difficult for foodservice operators to take corrective action appropriate to their specific application. Reducing food waste in an army kitchen can be very different from reducing waste in a hospital, for example.
Where food waste is stored in commercial operations for weekly collection, it is extremely difficult to determine each individual day's food waste rates without relying on an operator manually weighing and recording each load prior to disposal, which is expensive, time-consuming and open to error. Some waste collection vehicles have inbuilt weighing devices to monitor the loads collected, but these can be inaccurate and cannot distinguish between individual days' loads unless daily collections are undertaken, which is expensive, inconvenient, environmentally unfriendly, and counterproductive. Where food waste is disposed of by maceration, there is no means of monitoring food waste levels other than weighing and recording each load prior to maceration. This is also expensive, time-consuming and open to error.
Many food service operations use food waste digester machines to dispose of their food waste. The benefits of monitoring food waste by passing it through a food waste digester machine include the fact that it requires no additional time or effort on behalf of the operator, and the monitoring device cannot be bypassed, as in most operations the food waste digester machine provides the only means of food waste disposal.
Some food waste digester machines incorporate load sensing devices that weigh the food waste placed in the device by sensing the gross weight of the device and food waste, and then subtracting the net weight of the device. The problem with this type of device is that it cannot distinguish between food waste and contaminants like bones, cutlery, crockery, packaging etc., which can be erroneously placed in the device. It is also common for items to be placed on top of the machines or for operators to lean on the machines when loading. Food waste digester machines invariably use water as part of the digestion process, and it is not possible to accurately calculate the rates at which different foodstuffs absorb water prior to being digested. All of the above add to the inaccuracies of these devices.